This invention relates generally to calibrators and in particular to a portable oscillating pressure device for the dynamic calibraion of pressure transducers.
Prior dynamic transducer calibrations were made using a static calibration device to determine the sensitivity of the pressure transducer. Dynamic transducer calibration could be made at only one frequency in the kilo hertz range at amplitudes on the order of 0.01 psi using an acoustic calibrator with the transducer mounted in an adapting fixture accepted by the calibrator. The range of pressure and frequencies of interest in unsteady aerodynamic pressure measurements is from 0.1 to 2 psi and from 4 Hz to 200 Hz. The previous techniques do not satisfy the requirements outlined above because the dynamic calibration cannot be performed in situ at representative frequencies and oscillating pressures.
An object of the present invention is a method and apparatus to accurately measure the dynamic characteristics of pressure transducers installed in models and flight vehicles at the frequency and oscillating pressure ranges encountered during an unsteady pressure measurement test to establish that static and dynamic sensitivities are the same.
Another object of the invention is a method and apparatus to accurately measure the dynamic characteristics of pressure transducers in their installation configurations to determine if the installation configuration effects the amplitude and phase response as related to conditions on the surface of the model.
A further object of the invention is an apparatus that is portable and can accurately measure the dynamic characteristics of pressure transducers in situ.
Other objects and advantages of the present invention will be readily apparent from the following description and drawing which illustrates a preferred embodiment of the present invention.